Another inverter project, maybe a custom battery rack for under the coach.

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

supermanotorious

Well-known member
Joined
Jun 29, 2015
Posts
592
Location
Phoenix, AZ
I would like to do the same inverter project on this rig as I did on the old one. Given this trailer is heavier, I do not want to add any additional tongue weight. So I'd like to mount the batteries closer to the axles than the tongue. That presents a few challenges. For starters, there is no open air compartment to stow lead acid batteries at "floor" level so I'd have to put them under the trailer. This will take some fabricating and will be a PITA when trying to inspect and top off fluid levels. Also makes me wonder where the inverter would go for the shortest distance of battery cable length. And then there is tying in the relays to the system, extremely limited space for those components in this rig.

One benefit of this trailer is a 55 amp, 3-stage converter, the Sandstorm only had a 45amp converter.

Here is a link to the project I did on the Sandstorm: http://www.rvforum.net/SMF_forum/index.php/topic,91264
 

Attachments

  • 038.JPG
    038.JPG
    311.4 KB · Views: 155
https://www.amazon.com/dp/B00GZBHFMY

here is where I would likely mount the inverter, on a vertical mount secured to the cabinet supports, I could make a battery rack in-between the frame rails immediately underneath that or put them in-between the frame rails between the black and gray water holding tanks
 

Attachments

  • 002.JPG
    002.JPG
    268.3 KB · Views: 106
  • 003.JPG
    003.JPG
    194 KB · Views: 86
  • 004.JPG
    004.JPG
    212 KB · Views: 87
I don't see a place underneath where the batteries would not be so low as to risk knocking them off on some obstruction, or if a wheel drops in a rut and lowers the frame toward the ground. 

A short distance is optimal, but an adequate size cable compensates well enough. I would not be concerned about a run of several feet if that gave more practical choices.

Here are some alternate ideas on venting a battery in an enclosed space, e.g. a vented battery box:

https://www.amazon.com/NOCO-HM424-Sealed-Battery-Box/dp/B006VU5W92
http://www.zomeworks.com/battery-electronic-enclosures/hydrogen-venting-system/
http://www.expeditionportal.com/forum/threads/65346-DIY-vented-battery-box-what-to-use
http://www.tank-depot.com/product.aspx?id=741
 
I believe I would rather try venting a compartment to put the batteries in.  Or even building a sub-compartment in a larger compartment and venting it.
 
I considered the possibility of the batteries hitting the ground. There is limited area outside of the living area to build a box, the only storage is near the tongue and I'd prefer to have the batteries further back. Potentially if I put the frame rack between the axles, there would be little chance of them hitting the ground even in a rut. Any vented enclosure I build near the axles would be in the coach and I'm not a fan of that idea.
 
A new thought has come to mind, what if I got a flush mount access hatch, and install in the floor, in between the axles? I could put the batteries under the cabin there, and have access for topping off distilled water.
 
Sounds like a possibility, you will have to do some measuring to see if possible.
 
Another twist in this build is that the Onan generator is electric start off the battery bank, I assume I leave those cables alone, and add the heavy gauge wiring for the inverter?
 
slowly getting after this since we don't have any trips planned and it's barely starting to get cooler outside, I'm assuming the VCC is the battery charge output from the converter, correct? I'll interrupt it with a 12V 30amp relay as I've done before
 

Attachments

  • 005.1.jpg
    005.1.jpg
    100.3 KB · Views: 48
prepping the new 30amp relay for this toy hauler, realized I didn't need the "signal" cable to the relay since the 110v input goes to the normally open contacts and the relay coil, made these tabs to make the connection, when shore power comes in, it overrides the relay and passes itself on to the electric panel
 

Attachments

  • 005.JPG
    005.JPG
    245.8 KB · Views: 58
  • 006.JPG
    006.JPG
    237 KB · Views: 41
it's awesome to rebuild something you designed about a year ago, totally confident making all the terminals and connections, bought a couple of "project boxes" from stores today but returned them all, went with DIY and while old school- I'm happy with it and it cost nothing. all the relays are wired and working properly, I'll probably spend some time tomorrow cleaning up the wire runs and running the inverter's romex in to position
 

Attachments

  • 009.JPG
    009.JPG
    264.4 KB · Views: 56
  • 010.JPG
    010.JPG
    297.8 KB · Views: 48
  • 011.JPG
    011.JPG
    311.9 KB · Views: 50
with renewed energy today I decided to change things up a bit, rather than squeeze all the new components behind the converter, I took advantage of a rather large, unused space under the kitchen sink area, above the electrical panel "box", gave me another 1' or so of shore line and cleaned up the install so well, all I do is win win win no matter what

made that "L" bracket from an old bed frame.
 

Attachments

  • 014.JPG
    014.JPG
    313.9 KB · Views: 45
  • 001.JPG
    001.JPG
    240 KB · Views: 46
  • 002.JPG
    002.JPG
    288.1 KB · Views: 45
  • 007.JPG
    007.JPG
    234.5 KB · Views: 46
I love wood, and wood working, but maybe you should consider putting your 120VAC stuff in a metal enclosure. Things that have a capacity to burn don't play well with wood. Also a small gauge wire to connect the coil of your contactors to the AC would have been sufficient as the coil most likely pulls less than an amp. Hope this informational, not being critical.

Enjoy!
 
I appreciate all feedback, as long as someone isnt being belligerent, considered steel, heck I could've even TIG welded a box but I was concerned about arcing somehow, also, concerned about how to secure the relay in a box since I wanted flush sides all around
 
Not hostile at all, as I said not critical, no idea what your skill set is. I've seen metal aircraft burnt in half from electrical fires. Looking at a wood box with power relays brings up those visuals. You did good work and to be commended for taking on the challenge.

Again, enjoy
 
FINALLY mounted the inverter but of course this was after de-soldering the inverter from the receptacle circuits so I could hardwire it to the RV, I connected a temporary battery to the inverter and tested my automatic transfer system. IT WORKS FLAWLESSLY! The TV never knew it switched back and forth from shore power to inverter. All that's left now is to decide where the battery bank is going, and fabricate the box for them.

For the inverter, I drilled a 1/2" hole next to a receptacle and put in a grommet, to bring the output wires out of the inverter, then I extended them with soldered connections and heat shrink wrapped the soldering.
 

Attachments

  • IMG_2192.JPG
    IMG_2192.JPG
    319.4 KB · Views: 39
  • IMG_2193.JPG
    IMG_2193.JPG
    196.3 KB · Views: 28
  • IMG_2194.JPG
    IMG_2194.JPG
    284.4 KB · Views: 28
  • IMG_2195.JPG
    IMG_2195.JPG
    321.4 KB · Views: 27
  • IMG_2196.JPG
    IMG_2196.JPG
    324.9 KB · Views: 29
  • IMG_2197.JPG
    IMG_2197.JPG
    268.4 KB · Views: 29
  • IMG_2198.JPG
    IMG_2198.JPG
    327.2 KB · Views: 39
Nothing worth doing is ever easy, is it?! The termnals I bought from Amazon are great but dont fit over the inverter's lugs which are a non-standard M12 (of course). I carefully drilled them to 15/32" and they fit perfectly BUT they are not offset enough to not interfere with the lug housing on the inverter. So they need to be spaced outward. I was hoping to find some M12 nylon lock jam nuts at my Ace Hardware. They had M12 nylon locknuts and M12 jam nuts but no combo of the two as they do in standard sizes. So I'll space them out with a M12 split washer and call it good.

Now a question for you. I'm not sure how to route the remote turn on wire for the inverter. It seems all the wiring for switches etc come down from the ceiling. I have no idea how to fish the wire. How can I access anything?! I'd love to get the remote with the control panel for the water pump, gas station, generator, etc OR next to the thermostat. How would you fish the wire?
 

Attachments

  • 002.JPG
    002.JPG
    239.4 KB · Views: 27
  • 003.JPG
    003.JPG
    187.9 KB · Views: 25
  • 004.JPG
    004.JPG
    317 KB · Views: 34

Forum statistics

Threads
131,749
Posts
1,384,217
Members
137,520
Latest member
jeep3501
Back
Top Bottom